1. Field of the Invention
The present invention relates to a liquid strainer and in particular to a paint strainer.
The novel liquid strainer is generally made of a blank of paper or cardboard folded into a conical shape which is provided with a filter cloth about its apex.
The novel structural combination of the blank and the filter cloth results in a completely sealed strainer which prevents the escape of solid particles through slots in the folded filter cloth.
2. Prior Art
U.S. Pat. No. 4,158,631 to Whelan discloses a cone shaped paint strainer which has an apex made of non-filtering material. The filter cloth is provided only through wall openings extending above the apex, the wall openings being separated by wall portions obstructing the filtering operation of the strainer.
Although U.S. Pat. No. 4,362,624 to Ueda is directed to a double-deck strainer, the filter cloth is positioned in openings adjacent and above the apex, the latter being made of a non-filtering material such as paper or cardboard.
U.S. Pat. No. 3,567,033 discloses a paint strainer in the form of a cone containing diametrically disposed wall openings covered with a filtering material. The portion of the structure below the wall opening is imperforate and so constitutes a small internal well shaped pocket which prevents complete drainage of the paint from the receptacle.
U.S. Pat. No. 4,559,140 discloses a conical strainer having a pair of substantially diametrically opposed reinforcing arms formed integral with the upper portion of the cone and terminating at a pointed free end located at the apex of the cone. Both arms define a lower draining aperture and side filtration apertures. Once again, the reinforcing arms substantially obstruct the drainage of the strainer.
A conical strainer manufactured by Gerson Co. Inc. presents a structure which is intended to be improved by the proposed invention. The Gerson strainer has an upper support portion made of cardboard and a lower filtration portion. A pair of reinforcing arms extend integrally from the upper support portion. Each reinforcing arm bifurcates at its lower end and merges into a circular rim defining a draining apex portion. The filtering apertures are covered with a filtering cloth and located above the rim. The apex portion is made of filtering material folded about two folding lines in order to form a conically tapering drainage apex totally unobstructed by reinforcing arms of any sort. While the filtering apex portion provides an unobstructed drainage, it presents a major drawback since part of the folded filtering cloth making up the apex portion is not secured to any reinforcing structure. Under particular circumstances, a passageway between two adjacent layers of folded filtering material is susceptible of being formed. If a passageway is indeed formed, unfiltered liquid is proned to escape the filter and contaminate the filtered liquid.
The Gerson conical strainer is exhaustively described in the detailed description of the invention of this application.
Accordingly, the present invention relates to a conical strainer which circumvents the above mentioned disadvantages. The strainer embodying the invention is thus adapted to provide a totally unobstructed drainage area located in the apex portion of the cone so that the paint drains completely from the lower end of the filter.
Furthermore, the apex portion of the present invention is totally seal proof thus preventing contamination of the filtered liquid.